The most common method for long-term preservation of diagnostic tissue samples and specimen is formalin-fixation and paraffin-embedding. Molecular research and diagnostics are constantly dependent on robust and time-effective methods for extraction of high quality nucleic acids from tissue samples, in particular FFPE tissue samples. There are, however, challenges with regard to isolating nucleic acids in high yield, integrity and purity from FFPE tissue samples.
Standard methods for isolation of nucleic acids from FFPE tissue samples are time-consuming, often requiring overnight digestions.
U.S. Pat. No. 8,574,868 discloses a method for deparaffinizing an FFPE tissue. The method comprises mixing an FFPE tissue sample with an organic solvent and water or with an organic solvent and an aqueous solution. The density of the organic solvent is less than that of the water or the aqueous solution and the organic solvent is immiscible with the water or the aqueous solution. The resulting mixture is separated into an organic solution layer and an aqueous solution layer. Paraffin dissolved from the FFPE tissue sample is present in the organic solution layer and the deparaffinized tissue is in the aqueous solution layer and/or in an intermediate layer between the organic solution layer and the aqueous solution layer.